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How will oil palm expansion affect
biodiversity?
Emily B. Fitzherbert1,2, Matthew J. Struebig3, Alexandra Morel4, Finn Danielsen5,
Carsten A. Brühl6, Paul F. Donald7 and Ben Phalan8
1
Institute of Zoology, Zoological Society of London, Regent’s Park, London NW1 4RY, UK
Centre for Ecology, Evolution and Conservation, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ,
UK
3
School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
4
Environmental Change Institute, Oxford University Centre for the Environment, South Parks Road, Oxford OX1 3QY, UK
5
NORDECO, Skindergade 23-III, Copenhagen DK-1159, Denmark
6
Institute for Environmental Sciences, University Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
7
RSPB, The Lodge, Sandy, Bedfordshire SG19 2DL, UK
8
Conservation Science Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
2
Oil palm is one of the world’s most rapidly increasing
crops. We assess its contribution to tropical deforestation and review its biodiversity value. Oil palm has
replaced large areas of forest in Southeast Asia, but
land-cover change statistics alone do not allow an
assessment of where it has driven forest clearance
and where it has simply followed it. Oil palm plantations
support much fewer species than do forests and often
also fewer than other tree crops. Further negative
impacts include habitat fragmentation and pollution,
including greenhouse gas emissions. With rising
demand for vegetable oils and biofuels, and strong
overlap between areas suitable for oil palm and those
of most importance for biodiversity, substantial biodiversity losses will only be averted if future oil palm
expansion is managed to avoid deforestation.
extent to which oil palm has contributed to deforestation
[14,15].
The ecological impact of oil palm depends crucially on
the extent to which its expansion causes deforestation, and
on the extent to which it is able to support biodiversity.
Here we review the contribution of oil palm to deforestation, with a focus on Malaysia and Indonesia. We compare
the biodiversity value of oil palm plantations with that of
forest and alternative land uses to assess whether biodiversity loss can best be reduced by making plantations
more wildlife friendly or by linking yield increases with
habitat protection (Box 2). We review emerging opportunities to reduce the biodiversity impact of oil palm, identify
obstacles to success and gaps in current knowledge and
finally ask whether new initiatives are likely to reduce the
ecological cost of oil palm expansion.
Oil palm: one of the world’s most rapidly expanding
crops
Expansion and intensification of agriculture is the greatest
current threat to biodiversity [1–3]. Vegetable oils are
among the most rapidly expanding agricultural sectors
[4], and more palm oil is produced than any other vegetable
oil [5]. Global palm oil production is increasing by 9% every
year, prompted largely by expanding biofuel markets in the
European Union [6] (Box 1) and by food demand in
Indonesia, India and China [4].
Oil palm Elaeis guineensis is grown across more than
13.5 million ha of tropical, high-rainfall, low-lying areas, a
zone naturally occupied by moist tropical forest, the most
biologically diverse terrestrial ecosystem on Earth [7,8]
(Figure 1a,b). Malaysia and Indonesia produce more than
80% of all palm oil [9] (Figure 1d). Together, they also hold
more than 80% of Southeast Asia’s remaining primary
forests (mainly in Indonesia), where many endemic species
are threatened with extinction by some of the highest
global rates of deforestation [10–13] (Figure 1a). Environmental groups and industry representatives debate the
Contribution of oil palm expansion to deforestation
As with other crops [16], it is difficult to quantify the
extent to which oil palm has been a direct cause of
deforestation because of a lack of reliable data on land-cover change and incomplete understanding of its
complex causes. The usefulness of the most widely cited
land-cover data sets (those of the Food and Agriculture
Organization of the United Nations, FAO [11]) is undermined by changing definitions of forest, minimal independent monitoring of government statistics and a lack
of information on the subnational patterns and causes of
land-cover change [17–19].
Oil palm expansion could in principle contribute to
deforestation in four often indistinguishable ways: (i) as
the primary motive for clearance of intact forests; (ii) by
replacing forests previously degraded by logging or fire; (iii)
as part of a combined economic enterprise, such as with
timber, plywood or paper pulp profits used to offset the
costs of plantation establishment; or (iv) indirectly,
through generating improved road access to previously
inaccessible forest or displacing other crops into forests.
Land might also be deforested initially for other reasons
and then subsequently be planted with oil palm. In such
cases, oil palm could easily, but wrongly, be identified as a
Corresponding author: Phalan, B. ([email protected]).
0169-5347/$ – see front matter ß 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2008.06.012 Available online xxxxxx
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Box 1. Oil palm as a biofuel
Biofuels derived from palm oil and other biomass from plantations
can be used as alternatives to fossil fuels such as diesel. As a
substitute for diesel, palm oil is less suitable than other vegetable
oils owing to its high viscosity, lower energy density and high flash
point [66]. However, oil palm gives high yields at low prices, and
hence is likely to be important in meeting biofuel demand [5,67].
Global palm oil production increased by 55% between 2001 and
2006 (see http://faostat.fao.org), and will be further promoted by
increases in demand for biofuels generally. Given the substitutability of vegetable oils both for biodiesel production and most
edible uses [4], targets such as those set by the European Union to
promote biofuel use [6] will increasingly divert edible oils such as
rapeseed Brassica napus toward biofuel production. An increase in
the demand for any vegetable oil increases prices for all of them,
and further drives expansion, such as for both oil palm in Southeast
Asia and soybean Glycine max in Brazil. Even if the European Union
sources its palm oil exclusively from certified ‘sustainable’ sources
(such as producers signed up to the Principles and Criteria of the
Roundtable on Sustainable Palm Oil; see Box 3), it will be indirectly
supporting less responsible producers via higher prices.
The rationale for using biofuels is that they should be carbon
neutral, unlike fossil fuels which when burned release carbon stored
over millions of years. However, only if oil palm plantations are
established on degraded grasslands with low carbon content are
they likely to become net carbon sinks [35,68]. There are large
greenhouse gas emissions associated with forest clearance, desiccation of peat soils and use of fossil fuels for plantation cropping,
processing and transport [62,63,68,69]. It will take decades or
centuries for the avoided carbon emissions from fossil fuels to
compensate for emissions released when forest or peat soils are
converted [35,69]. Until it is demonstrated that oil crops are no
longer replacing forests, the use of palm and other vegetable oils as
biofuel feedstock is likely to exacerbate climate change, drive up
food prices and hasten biodiversity loss.
driver of deforestation. However, oil palm is also used as a
pretext by companies to obtain permits to clear land for
other purposes, and cannot easily be excluded as a contributing factor.
Malaysia
Oil palm was first planted commercially in Peninsular
Malaysia in 1917, where it replaced rubber plantations
and forest [7,20] (Figure 1d). As land became scarce,
expansion shifted to Sabah and Sarawak, often in association with logging [18,21,22], and was facilitated by the
reclassification of some state forest reserves to allow conversion to plantations [18,21]. Between 1990 and 2005 the
area of oil palm in Malaysia increased by 1.8 million ha to
4.2 million ha (see http://www.mpob.gov.my), while 1.1
million ha of forest were lost [11] (Figure 1d). It has been
estimated that at least 1.0 million ha of forest were
replaced by oil palm over this period [23], but this estimate
does not consider forest conversion into unproductive land,
nor whether oil palm caused or simply followed deforestation.
Indonesia
Commercial oil palm cultivation started in Sumatra in
1911; expansion to other parts of Indonesia did not occur
until the 1980s [7] (Figure 1d). Today, ambiguities in the
land tenure system and corruption [13], combined with
increased regional autonomy, have made it easier for
timber, plywood and paper pulp companies to obtain per2
Trends in Ecology and Evolution Vol.xxx No.x
mission to clear millions of hectares of forest under the
pretext of plantation establishment, without later planting
them, especially in Kalimantan [22,24,25]. Oil palm plantations often replace forests previously degraded by fire
and logging [17,26], and illegal oil palm development has
been reported inside protected areas [4,15]. Between 1990
and 2005 the area of oil palm increased by 4.4 million ha to
6.1 million ha (see http://www.deptan.go.id), while total
forest loss was 28.1 million ha [11]. Hence, conversion to oil
palm could account for at most 16% of recent deforestation.
It has been estimated that 1.7–3.0 million ha of forest were
lost to oil palm over this period [23]. The uncertainty
surrounding these estimates is high and, as they exclude
changes in unproductive land area and include only mature oil palm area, they could be over- or underestimates
(see http://faostat.fao.org).
Elsewhere, oil palm has been documented as replacing
forest in southern Thailand [27], Myanmar [28] and Papua
New Guinea [29].
The future
Although the extent to which oil palm has been a direct
cause of past deforestation is difficult to quantify, its
potential as a future agent of deforestation is enormous.
Demand for palm oil is predicted to continue increasing [5],
and globally, most of the remaining areas suitable for
planting are forested. At present, relatively little oil palm
is grown outside Southeast Asia, but 410–570 million ha of
currently forested land across Southeast Asia, Latin America and Central Africa are potentially suitable for oil palm
cultivation (Figure 1c) (http://www.whrc.org/resources/
published_literature/pdf/WHRC_REDD_crop_suitability.pdf) and might be increasingly utilised as demand rises
and agronomic advances are made.
Effects of converting forests to oil palm plantations
An understanding of how much biodiversity oil palm plantations can support is essential to direct conservation
action. If plantations are consistently depauperate relative
to forests, the focus should be on stopping deforestation.
Alternatively, if the management of plantations can be
adapted so that they support a substantial proportion of
forest species while maintaining high yields, conservation
effort should focus on ways to enhance biodiversity in
plantations [3].
The response of biodiversity to land-cover change
depends upon the extent to which natural habitat features
are replicated and upon variation in the sensitivities of
species to change [30]. Oil palm plantations are structurally less complex than natural forests, with a uniform tree
age structure, lower canopy, sparse undergrowth,
less stable microclimate and greater human disturbance
[31–33] and are cleared and replanted on a 25–30 year
rotation [7].
To assess the effect of palm oil on biodiversity, we
conducted a literature survey. Publications on biodiversity
make up less than 1% of the scientific literature on oil palm
since 1970 [34]; we could find no published studies of plants
(but see Ref. [35]) and just 13 of animals [23,31–33,35–43]
that compared biodiversity in oil palm plantations with
that in forest.
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Trends in Ecology and Evolution
Vol.xxx No.x
Figure 1. Global distribution of oil palm and potential conflicts with biodiversity: (a) areas of highest terrestrial vertebrate endemism (ecoregions with 25 or more endemics
are shown); (b) global distribution of oil palm cultivation (harvested area as percentage of country area); (c) agriculturally suitable areas for oil palm (with and without
forest); and (d) oil palm-harvested area in Southeast Asia. In (b) and (d), Brazil, Indonesia, Malaysia, the Philippines and Thailand are subdivided by province, but other
countries are not. Data are for 2006, except for the Philippines and Thailand, where 2004 data are the most recent available. (Sources: [a] World Wildlife Fund (2006)
WildFinder: online database of species distributions, version Jan-06, http://www.worldwildlife.org/wildfinder; [b,d] world: http://faostat.fao.org; Brazil: http://
www.ibge.gov.br/estadosat; Indonesia: http://www.deptan.go.id; Malaysia: http://econ.mpob.gov.my/economy/annual/stat2006/Area1.7.htm; Philippines: http://
www.bas.gov.ph/downloads_view.php?id=127; Thailand: http://www.oae.go.th/statistic/yearbook47/indexe.html; [c] forest area: European Commission Joint Research
Centre [2003] Global Land Cover 2000 database, http://www-gem.jrc.it/glc2000; oil palm suitability: updated map from G. Fischer, first published in Fischer et al. [65], http://
www.iiasa.ac.at/Research/LUC/SAEZ).
Species richness
Oil palm consistently held fewer than half as many
vertebrate species as primary forests, whereas invertebrate taxa showed more variation [35] (Figure 2a). Oil
palm also had much lower species richness than disturbed
(logged or secondary) forests, although the differences were
not so great (Figure 2b). One study of bees found more
species in oil palm than in forests, but might have underestimated species richness in forests because the canopy
was not sampled [39]. Across all taxa, a mean of only 15% of
species recorded in primary forest was also found in oil
palm plantations.
Box 2. Linking production to conservation
Increasing the productivity of existing oil palm plantations, for
example by better management of harvesting to improve oil yield
[7] (see Ref. [70]) could potentially reduce the need for more land to
be cleared (the ‘land-sparing’ option of Ref. [3]). However, this will
only generate a conservation gain if it is linked to the protection of
natural habitats, for example through strategic land-use planning and
implementation. Our review of the value of oil palm plantations for a
wide range of taxa suggests that a land-sparing approach that
ensures the conservation of intact forests would be more beneficial
than the promotion of wildlife-friendly management practices within
planted areas.
With higher yields per unit area for both large-scale commercial
enterprises and small holders than many alternatives, oil palm might
provide a substitute for traditional subsistence agriculture and could
reduce the area of land needed to support each household [7,25].
However, rural communities do not always welcome plantation
development [17], and care must also be taken that labourers do
not increase the pressure on natural habitats near plantations [25].
Successful land sparing is contingent upon inelasticity of demand for
agricultural products [3]. The substitutability of vegetable oils ensures
that demand for any one oil is elastic and, although future global
requirements for edible oils are reasonably predictable, demand will
become effectively limitless if driven by new biofuel markets.
Estimated annual world biodiesel requirement by 2050 could be 277
million tons, twice current total vegetable oil production and seven
times total palm oil production [67].
There are possibilities for conservation partnerships between oil
palm producers, conservation practitioners and rural communities
which would enable financial resources from oil palm to be
channelled into forest conservation efforts, such as local capacity
building in legal aspects of forest law and enforcement [50,71,72].
Recent proposals for nongovernmental organisations to use oil palm
agriculture to acquire private reserves [9] are unlikely to be the most
cost-effective approach [72]. There might be more scope for
producers to contribute to payments for environmental services
schemes aimed at slowing deforestation [73], and to conserve forest
remnants within their plantations. Strategic alliances between multiple stakeholders, such as oil palm producers, environmental organisations, rural communities, government agencies and carbon offsetters, have the largest chance of success [72].
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Figure 2. The biodiversity impact of converting forests to plantations is shown by comparing species richness and forest species richness in (a) oil palm relative to primary
forests, (b) oil palm relative to degraded (logged and secondary) forests and (c) rubber relative to primary forests. Species richness is scaled so that forest richness in
primary or degraded forests equals 1. Each vertical column contains a study of one taxon (NA = not applicable). In most taxa, the highest species richness is found in
primary forests. There is a large reduction in species richness in oil palm compared with both primary and degraded forests, illustrated by the gap between the bars and the
line of forest equivalence. The reduction in forest species richness is even more marked in most taxa. Rubber plantations show a similar loss of species richness compared
with primary forests, but retain a higher species richness and/or forest species richness of some taxa. In no study does rubber have lower species richness than oil palm.
Species composition and abundance
Most studies found large differences in faunal species
composition
between
oil
palm
and
forests
[27,32,35,36,39,40]. The species lost were not a random
subset of the original forest fauna, but tended to include
species with the most specialised diets, those reliant on
4
habitat features not found in plantations (such as large
trees for cavity-dwelling species), those with the smallest
range sizes and those of highest conservation concern
[27,31,33,41]. Plantation assemblages were typically dominated by a few abundant generalists, non-forest species
(including alien invasives) and pests [27,32,41]. Forty
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percent of the ant species found in oil palm plantations in
Malaysia were aliens, including the highly invasive crazy
ant Anoplolepis gracilipes [43]. Densities of rats (e.g. Rattus tiomanicus) can reach 600 per ha [44], providing abundant food for predators such as blood pythons Python
brongersmai [45], barn owls Tyto alba [44] and leopard
cats Prionailurus bengalensis [46].
Caveats
Several methodological shortcomings are likely to reduce
the apparent difference in biodiversity measures between
forest and oil palm, so our estimates of biodiversity loss are
likely to be conservative [35,47,48]. For example, it is more
difficult to detect many taxa in rain forests, because rain
forests have a taller canopy and more structural complexity than plantations [31]. Also, estimates of species richness from small areas of oil palm [32,36,38,42] or near
forest edges [27,40] will be artificially inflated by the
presence of transient species from nearby forests. Even
standardising results based on effort (which was not done
in most studies) does not fully remove these biases [27,48],
especially when only a small number of species are
sampled [31,37,38]. Finally, a time lag between habitat
loss and extinction [10] might lead to the recording of some
species in oil palm plantations that cannot ultimately
persist there.
Comparison with other land uses
To understand the relative impacts of converting different
prior land covers (forest and other crops) to oil palm, and of
converting forest to oil palm rather than to other crops, we
examined studies which made such comparisons. Rubber
Hevea brasiliensis supported as many or more species as oil
palm, and more forest species (Figure 2a,c). Cocoa Theobroma cacao had similar [38] or higher [36] species richness, but not always more forest species. Coffee Coffea
canephora supported higher ant species richness and more
forest species [36]. Acacia mangium plantations had
higher beetle species richness than oil palm, and species
composition was closer to that in forest [32]. There was
greater overlap in species composition between oil palm
and other tree crops than there was with forest [27,36,40].
Compared with oil palm, pasture and urban mown grassland had lower species richness, gardens of mixed crops
had similar or higher species richness and abandoned
pasture had more species [33,36,38]. Imperata cylindrica
grasslands (which cover at least 8.5 million ha in Indonesia
alone [49]) had more species of ants than oil palm, but
fewer forest species [36].
In summary, oil palm is a particularly poor substitute
for either primary or degraded forests, and whereas any
conversion of natural forest is inevitably damaging to
biodiversity, oil palm plantations support even fewer forest
species than do most other agricultural options.
Landscape scale effects
Because oil palm and other tree crops are unsuitable
habitats for most forest species, plantations, where they
form part of the landscape matrix, can act as a barrier to
animal movements [50,51]. Thus, forest fragments isolated
within oil palm plantations supported fewer than half as
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Box 3. Regulating development: the RSPO and public
disclosure
Although increasing consumption of palm oil has promoted oil
palm expansion, consumer concern has helped stimulate a movement toward more environmentally responsible practices within the
industry. The most important initiative is the Roundtable on
Sustainable Palm Oil (RSPO; see http://www.rspo.org), whose
members manage more than one-third of the global oil palm area,
and which has developed a set of environmental and social
Principles and Criteria for producers. Commitments to reduce
impacts on biodiversity using the High Conservation Values
approach to identify forests and other areas for preservation are
included [74], but difficulties remain in defining and applying these
values consistently. One area of concern is that forests degraded by
logging are generally assumed to have low conservation value,
when this is often not the case [47]. There are also challenges in
ensuring compliance, and in certifying the activities of small-holder
farmers who supply palm fruits to RSPO producers. The auditing
and certification system was only agreed to in November 2007, and
thus RSPO-certified palm oil will not be available before late 2008.
Governments are not directly involved in the RSPO, but have
responsibility under international conventions to ensure that neither
RSPO members nor other producers contribute to biodiversity loss
[12]. It will take time for governments and legal institutions to
become more effective and, in the meantime, voluntary or informal
methods can be useful in providing some degree of regulation. To
this end, ‘public disclosure techniques’ can help to provide effective
environmental governance. A growing body of evidence suggests
that in countries where regulatory agencies are weak, such as
Indonesia, the regular collection and dissemination of information
about the environmental performance of companies can lead to
increased compliance with regulations, with minimal burden on
regulators [75]. Disclosure works both by increasing external
pressures on firms and by improving the access of managers to
information about the impacts and mitigation opportunities of their
companies. Disclosure for visible, well-known attributes such as
forest fire is likely to have the most impact (see e.g. http://
www.eyesontheforest.or.id). Public disclosure programmes can
quickly lose credibility if information is mishandled, so accurate
reporting and independent auditing is essential [75].
many ant species as nearby continuous forests, and a
greater number of invasive ‘tramp’ species were found in
the smallest fragments [52]. Small, isolated forest fragments surrounded by oil palm had lower species richness
and diversity of butterflies than larger, less isolated fragments [53].
As well as decreasing area and connectivity, fragmentation increases the length of forest edge exposed to harmful
edge effects [30]. Abiotic edge effects include increased
vulnerability to wind, desiccation and fire [30,54], although
mature plantations of oil palm and other tree crops might
provide more protection to forest edges than treeless
habitats. Biotic edge effects include increased tree sapling
mortality in forests where densities of wild pigs Sus scrofa
are elevated by increased food availability in nearby oil
palm plantations [55].
Impacts of plantation development and management
As with other crops, the biodiversity impacts of oil palm
depend on how the crop is developed and managed. Many
of the greatest impacts result from the initial process of
land clearance and preparation. Fire, whether used deliberately to clear forest or spreading accidentally from
agricultural land, kills seeds and sedentary animals
[54]. Many of the larger palm oil producers (Box 3) have
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committed to avoid using fire in land preparation and when
mature, oil palm landscapes are probably less susceptible
than Imperata grasslands to the spread of uncontrolled
fires [17]. Initial land clearance exposes the soil to erosion.
Sediment loads in streams increase dramatically after
land clearance but return to baseline levels after plantation establishment [56]. Establishment of plantations on
peat soils and where they replace forest contributes substantially to greenhouse gas emissions (Box 1), and thus to
climate change, a growing global threat to biodiversity
[35,57]. Despite these negative impacts, oil palm plantations might be better at providing some ecosystem services
(such as carbon sequestration and soil protection) than
annual crops or grassland, but not if they replace forest or
peatland (Box 1).
Following plantation establishment, the greatest
environmental impacts are likely to come from pollution.
Water pollution from plantations and onsite mills is likely
to affect aquatic biodiversity [58], but such impacts have
not been assessed in relation to oil palm. Potential pollutants include palm oil mill effluent (POME), fertilisers,
insecticides, rodenticides and herbicides [7,41,44]. Efforts
to reduce the impacts of some of these pollutants are
already in place in some plantations. POME is usually
purified, so it can be harmlessly discharged into rivers;
widespread use of integrated pest management and leguminous cover crops reduces use of insecticides and herbicides; and oil palm requires less fertiliser per unit of output
than other oil crops [4,7].
There appear to be few biodiversity-friendly management practices which could enhance the value of oil palm
plantations for native species. There are fewer animal
species in planted areas because of reductions in habitat
structural complexity and plant species diversity
[27,32,38], and opportunities to increase these while maintaining agricultural productivity are limited [59]. Species
Trends in Ecology and Evolution Vol.xxx No.x
richness of birds and butterflies was only marginally
higher in oil palm plantations with more epiphytes or
undergrowth [27,59]. Planting nonnative plants (such as
Euphorbia heterophylla in Malaysia) to attract beneficial
insects might help in pest control, but does not significantly
improve the biodiversity value of plantations [59]. A tradeoff might exist between enhancing the biodiversity value of
plantations and minimising expansion into forested areas:
if biodiversity-friendly management reduces yields, then
more land will be needed to achieve production targets [3].
In this context, the limited available evidence suggests
that the potential of biodiversity-friendly management is
minimal (Box 2).
Of much greater value to biodiversity is the protection of
fragments and corridors of native forest within and around
plantations, including riverside buffers and remnants on
steep slopes [59]. For species able to move through the oil
palm matrix, forest fragments can act as ‘stepping stones’
for dispersal, and can be more beneficial than habitat
‘corridors’ [60], especially if they are large and not too
isolated from other forests [53]. Although forested areas
of tens of thousands of hectares will be needed to avert the
extinction of many species [61], even small and degraded
fragments can hold considerable biodiversity value and
complement the species in larger reserves [50,51,53].
What can be done to mitigate the impacts?
Although there is value in protecting forest remnants,
there seem to be few other opportunities to improve the
biodiversity value of oil palm plantations, and the future
ecological impact of oil palm will be determined largely by
the extent to which it causes large-scale deforestation.
Governments, environmental and social organisations,
scientists, producers, financial institutions, buyers and
consumers together have the capacity to soften the impact
of palm oil production on biodiversity. Although the best
Box 4. Outstanding questions
The value of conservation research depends upon its ability to
stimulate informed action by policymakers and practitioners [76].
Robust answers to the following, often multidisciplinary, questions
will help to inform policy and conservation action.
Preventing oil palm-driven deforestation
Ensuring that the expansion of oil palm plantations does not occur at
the expense of tropical forests is of the highest priority if ecological
damage is to be minimised, and will be aided by well-informed and
effectively implemented strategic landscape planning.
(i) How can the contribution of oil palm development to land-cover
change be effectively determined and monitored?
(ii) How is oil palm development linked to other drivers of land-cover
change in different regions and at different scales?
(iii) Do current methods of determining High Conservation Value
areas ensure the protection of areas of conservation importance?
(iv) Is it safe to assume that marginal non-forest lands, for example
Imperata grasslands, are of low conservation value?
(v) Where can oil palm expansion be directed to maximise agricultural yields and minimise impacts on biodiversity and climate?
Conservation strategies in an oil palm-dominated landscape
There is now sufficient evidence to conclude that the biodiversity
value of oil palm plantations is low in comparison with forest,
6
but little is known about the influence of different plantation
management strategies and landscape configurations on native
species.
(i) What are the impacts of oil palm cultivation on freshwater and
marine ecosystems?
(ii) Can oil palm yields be increased while limiting negative
externalities such as aquatic pollution?
(iii) Are there economically acceptable ways to make oil palmdominated landscapes more biodiversity friendly (e.g. by increasing functional connectivity) without reducing yields?
(iv) What is the long-term potential for species persistence within oil
palm-dominated landscapes?
Policy and markets
The applicability of conservation research depends upon the integration of biological, social, political and economic concerns.
(i) What are the barriers to the implementation of strategic landscape planning and how can they be overcome?
(ii) How can responsible oil palm development be best promoted,
monitored and enforced?
(iii) How will the attitudes of consumers in developing palm oil
markets (especially in Asia) affect future demand?
(iv) How will biofuel policies and markets affect oil palm
expansion?
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strategies for impact mitigation will differ within and
between countries, there are several emerging opportunities.
Governmental and nongovernmental organisations can
work to develop national strategies for land allocation that
integrate maps of conservation priorities and agricultural
suitability. Such strategies give no assurance that impacts
are being minimised unless they are integrated into landuse allocation and coupled with effective regulatory systems. Diverting oil palm expansion into areas of low conservation importance (e.g. degraded Imperata grasslands,
not to be confused with degraded forests) would avert much
ecological damage. However, current international policies
are doing nothing to ensure that such areas are being used
in preference to natural forests, and difficult issues such as
governance and land tenure need to be tackled effectively
in producer countries. A challenge for conservation scientists is to understand these issues and identify solutions
(Box 4). Nongovernmental organisations can help increase
transparency by disseminating information to plantation
managers and other stakeholders (Box 3).
Producers must be given access to information that will
allow them to locate new plantations in areas where they
will cause the least ecological damage. There is considerable scope for more widespread use of comprehensive
Environmental Impact Assessments of proposed plantations, including Life-Cycle Analyses, to identify and reduce
impacts [62,63]. There are opportunities for identifying
ways in which palm oil yield can be increased while minimising negative environmental externalities (Box 2).
There might also be wildlife-friendly management practices that do not reduce yields (but sometimes even
enhance them [64]), and opportunities for companies to
promote awareness of biodiversity among their staff [34].
Some producers have made significant progress toward
minimising the adverse impacts of palm oil production, but
challenges remain (Box 3). Strategic alliances between
producer companies, environmental organisations and other stakeholders will be needed for conservation efforts to
be successful (Box 2).
Financial institutions, buyers and consumers can assist
by continuing to demand detailed evidence that producers
are doing all they can to minimise the negative impacts of
palm oil production, and by denying finance and markets to
those that are not. Such evidence will be most credible if
independently audited, for instance by local nongovernmental organisations (Box 3). It is difficult to predict how
quickly emerging markets (e.g. in India and China) will
start to demand evidence of environmental responsibility,
but this could be critical in determining whether irresponsible and unregulated producers continue to make a profit,
and hence whether oil palm expansion comes at great cost
to forests.
Conclusions
For biodiversity, oil palm plantations are a poor substitute
for native tropical forests. They support few species of
conservation importance, and affect biodiversity in adjacent habitats through fragmentation, edge effects and
pollution. There is enough non-forested land suitable
for plantation development to allow large increases in
Trends in Ecology and Evolution
Vol.xxx No.x
production without further deforestation, but political
inertia, competing priorities and lack of capacity and understanding, not to mention high levels of demand for
timber and palm oil from wealthy consumers, often make
it cheaper and easier to clear forests. The efforts of some
producers to reduce their environmental impacts, especially by avoiding forest conversion, must be commended.
However, unless governments in producer countries
become better at controlling logging, protecting forests
and ensuring that crops are planted only in appropriate
areas, the impacts of oil palm expansion on biodiversity
will be substantial.
Acknowledgements
We thank William Laurance, Lian Pin Koh, Hereward Corley, Reza Azmi,
Andrew Balmford, Jos Barlow, Chris Carbone, Rona Dennis, Mikkel
Funder, Toby Gardner, Jenny Gill, Rhys Green, Tom Maddox, Erik
Meijaard, Lesley Potter, Ed Turner and an anonymous reviewer for
useful comments and discussion, and Ana Rodrigues, Tiffany Bogich and
Günther Fischer for assistance with figures.
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